【答案解析】A fixed action pattern refers to animal's innate behaviors that are usually unchangeable and often conducted to completion once started. The professor discusses two examples to illustrate how animals behave in a fixed pattern. Male crested puffers tend to attack fish with red marks, and they will ignore those invaders without red marks on their bodies. Another case is the female goose. It is inclined to move its head around to protect its ducklings after laying the eggs. Interestingly, it kept doing this even after the eggs are moved out of the nest. [听力原文] M: When stimulated by certain signals, animals would display some behaviors out of their nature, and that is what we call as fixed action patterns. Some actions are common to all members of a species to the extent that different members of a species tend to perform the behavior in a recognizably similar fashion. There was a kind of fish called red-tailed crested puffer living in the tropical ocean nearby the Caribbean Sea. The male crested puffer tends to attack those with red mark who enter its territory carelessly. However, the crested puffer just ignores those without the red mark and can live peacefully with the invaders. Another case is female goose. After laying eggs, a female goose is inclined to move its head back and forth instinctively. Interestingly, after moving their eggs out of the nest, the female goose continued to move its head to and fro. These are two examples of fixed patterns of animal behavior.